(a) Field of the Invention
The present invention relates to a method and an apparatus for controlling torque intervention of a hybrid electric vehicle. More particularly, the present invention relates to a method and an apparatus for controlling torque intervention of a hybrid electric vehicle that determines a final engine torque and a final motor torque by directly applying an intervention torque based on a torque intervention request to a demand torque of a driver and by simultaneously controlling torque reduction based on a demand torque of a driver.
(b) Description of the Related Art
Generally, a hybrid electric vehicle is driven by an engine that generates torque from fuel combustion and an electric motor that generates torque from an electric battery. The hybrid electric vehicle includes a hybrid control unit (HCU) that executes an engine operation of the hybrid electric vehicle, an engine control unit (ECU) that executes an operation of an engine, a motor control unit (MCU) that executes an operation of the driving motor, a transmission control unit (TCU) that executes an operation of the transmission, and a battery management system (BMS) that manages a condition of a battery. Among these controllers, the TCU is configured to request torque reduction while the hybrid electric vehicle is being shifted to prevent shift shock and protect a transmission.
A traction control system (TCS) is configured to prevent wheel spin when a vehicle starts or accelerates on a snowy or icy road by controlling a brake and an engine and improves driving stability. Thus, the TCS of the hybrid electric vehicle is also configured to request torque reduction while a tire of a hybrid electric vehicle is sliding on the snowy or icy road due to an overabundant driving torque during starting or acceleration of the vehicle.
A traditional control method of torque reduction of a hybrid electric vehicle using intervention torque implements a control logic that is the same as a control method of torque reduction used by a vehicle with a singular power source. The vehicle with a singular power source separates the ECU and the TCU/TCS, to allow the vehicle with a singular power source to execute torque reduction by comparing a torque instruction of the ECU with a torque instruction of the TCU/TCS and by collaborating the ECU with the TCU/TCS when the TCU/TCS has requested torque reduction.
Similarly, the hybrid electric vehicle controls torque reduction by considering torque instruction of an engine or a motor based on a demand torque of a driver when the HCU requests torque reduction based on an intervention torque. However, this developed control method executes torque reduction at the last step, so that the control method may not choose an operation point considering system efficiency. In addition, the control method may have a negative influence on the fuel efficiency since power of an engine and a motor is distributed for a corresponding request amount of an intervention torque in an allowable range of SOC.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.